Sound record



Patented Jan. 28, 1936 UNITED STATES SOUND RECORD Samuel Whyte, Redhill, Surrey, England, assignor to Electric and Musical Industries Limited, Middlesex, England, a company of Great Britain No Drawingm Application August 22, 1931, Serial No. 558,828. In Great Britain August 26, 1930 Claims.

The present invention relates to sound records of the kind adapted to operate a reproducing stylus. More particularly the invention relates to records of this kind which comprise a phenol formaldehyde resinous condensation product, with or without accelerators, modifying agents or filling material.

It has been found that with records, the playing surface of which is prepared from a phenol condensation product such as a resorcinol formaldehyde condensation product, needle drag is considerable and the records frequently will not play satisfactorily on a machine having a weak driving motor.

It is an object of the present invention to remove this objection.

According to the present invention a sound record material comprises a phenol formaldehyde condensation product with which there is incorporated a soap. Preferably, a water soluble soap is used in the record material of the invention. The condensation product may be derived from phenol itself (monohydroxy-benzene) or from a dihydric phenol such as resorcinol.

Plasticismg or modifying agents such as glycerine, glyceryl derivatives, chlorinated hydrocarbons e. g. chloronaphthalene, or the like my be incorporated in the material of the present invention for the purpose of increasing the plasticity or flexibility thereof. The record material may also contain filling material.

An example of a mixture which has been found suitable for the preparation of a sound record is as follows:-

The soft soap used may be that obtained from linseed oil and caustic potash and contains a considerable amount of glycerine. Other soft soaps or hard soaps obtained by the combination of caustic potash or soda with fats or fatty oils with or without resins may, however, be used.

In preparing a record from this mixture the resorclnol and formalin are heated together for about one hour at a temperature of approximately 70 C. until a syrup is obtained. The remaining components are then added to this syrup and thoroughlymixed therewith,the wholebeingmilled to a smooth paint-like consistency. The mixture is hardened by drying in the usual manner at a low temperature, the hardened mass ground to powder and the latter pressed under heat between the record carrying matrices, or the powder may first be lightly compressed to form a billet which is then pressed under heat between the matrices. In this manner, a homogeneous disc 5 record is produced. It is to be understood of course that the hardening of the syrup mixture is not to he proceeded with to such an extent that a product is obtained which cannot still be moulded. The heat and pressure applied in the record press renders the record produced hard and infusible. For the preparation of a laminated record having a core or support of paper, cardboard or the like, the milled syrup mixture is spread onto strips of the material forming the core or support. If necessary, the syrup mixture is thinned with alcohol before being spread. The coated strips are then dried and cut into discs which are impressed with the sound groove between heated matrices.

The free alkali in the soap acts as an accelerator of the hardening of the record material. Further alkali however, may be added to the mixture, if it is desired to obtain a substance which hardens more rapidly in the press. 5

I do not wish to be limited to the specific chemicals, amounts, temperatures, times of treatment, or steps of processes described above, except insofar as is necessitated by the prior art and by the spirit of the appended claims, since these are given merely as a means for clearly describing my invention.

I claim as my invention:

1. Sound record material comprising a phenol condensation product having a soft water soluble soap incorporated therein.

2. Sound record material comprising a phenol condensation product adapted for rapid hardening under the action of heat and having a soap incorporated therein. 40

3. Sound record material comprising a phenol condensation product adapted for rapid hardening under the action of heat by the incorporation of free alkali therein and including a soap.

4. A laminated sound record structure comprising a core of sheet material and a layer of sound groove receiving material comprising a phenol condensation product having a soap incorporated therein.

5. A laminated sound record structure comprising a core of sheet material and a layer of sound groove receiving material comprising a resorcinol formaldehyde condensation product and having a water soluble soap incorporated therein.

SAMUEL WHY'I'E. 

